Limit orders, routing paths, and commission tradeoffs

Score the ticket by type and path

A market order is an unpriced instruction to trade as soon as a venue will accept it, and it was often the only order type that qualified for a retail firm's lowest posted commission. A limit order is a priced instruction that caps the worst acceptable fill and can be used to request an immediate match at or inside the displayed quote.

Order routing is the path an instruction takes after it leaves the trader, including a broker desk, a third-party buyer of order flow, an exchange specialist, or an electronic communications network.

Editorial view: score a ticket by order type and routing path first. Those choices decide who can trade against the order, how long a fill can wait, and whether a priced instruction is the cheaper way to control implementation cost. The advertised commission is a filter on the fee line, not the full trade cost.

Treat the posted commission as a filter

In retail accounts of the period, the most favorable posted commissions generally applied only to unpriced market orders, while priced limit orders could incur an extra fee.

Commission analysis compares the posted fee for an order type with the slippage and internalization profit that can arise on the same ticket.

Editorial view: keep the posted schedule in the comparison, but do not let it stand in for implementation cost. Implementation cost is the combined effect of commissions, delay, and fill price versus the quote that was visible when the order was sent.

Follow the order after it leaves

After a brokerage received an order, it could trade against the customer, sell the order to a third party, or forward it to an exchange or an electronic communications network.

Simultaneous market buy and sell interest in the same stock created an incentive for an intermediary to buy on the bid and sell on the offer rather than sending both orders out immediately.

Discounted commissions were often offset by pricing profit from that internalization, so a small commission saving could be dominated by larger slippage on the fill.

Editorial view: the routing path decides who can trade against the order. A small fee saving on an internalized market order can still be the more expensive ticket once slippage is counted.

Compare limit and market handling on a direct path

Limit orders sent on a direct electronic turnaround path to the exchange could be filled immediately by the assistant specialist at the then-best bid or offer.

Market orders on that venue were often batched and held for a few seconds, a window in which the stock price could change. That short delay is a specialist-hold: market orders wait at the exchange post while the quote can move.

Entering a buy limit above the offer or a sell limit below the bid was used to seek a faster fill while still receiving a better price than the limit entered. That better fill is price improvement.

Editorial view: on this path, a priced instruction can request an immediate match at or inside the displayed quote and can avoid the specialist-hold that leaves an unpriced ticket exposed to a moving quote. That is one way a limit order can be the cheaper control on implementation cost even when the posted commission is higher.

Put the fee last in the score

Editorial view: a complete ticket score starts with order type and routing path, then checks specialist-hold risk and any price improvement, and only then applies commission analysis as a residual filter. The advertised commission remains part of implementation cost. It is not the whole cost.